Document Type
Article
Publication Date
8-16-2011
Publication Title
Proceedings of the National Academy of Sciences of the United States of America
Department
Thayer School of Engineering
Abstract
Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. Biochemical assays confirm a complete loss of NADH-dependent activity with concomitant acquisition of NADPH-dependent activity, which likely affects electron flow in the mutant. The simplicity of the genetic basis for the ethanol-tolerant phenotype observed here informs rational engineering of mutant microbial strains for cellulosic ethanol production.
DOI
10.1073/pnas.1102444108
Original Citation
Brown SD, Guss AM, Karpinets TV, Parks JM, Smolin N, Yang S, Land ML, Klingeman DM, Bhandiwad A, Rodriguez M Jr, Raman B, Shao X, Mielenz JR, Smith JC, Keller M, Lynd LR. Mutant alcohol dehydrogenase leads to improved ethanol tolerance in Clostridium thermocellum. Proc Natl Acad Sci U S A. 2011 Aug 16;108(33):13752-7. doi: 10.1073/pnas.1102444108. Epub 2011 Aug 8. PMID: 21825121; PMCID: PMC3158198.
Dartmouth Digital Commons Citation
Brown, Steven D.; Guss, Adam M.; Karpinets, Tatiana V.; and Parks, Jerry M., "Mutant Alcohol Dehydrogenase Leads to Improved Ethanol Tolerance in Clostridium Thermocellum" (2011). Dartmouth Scholarship. 1532.
https://digitalcommons.dartmouth.edu/facoa/1532
